Cordova Writing On An Existing File If Already Available (updating data)

cordova writing file.js

var fileName = 'test-450.json';
var fileData;
var savedFileEntry = {};

promise_getPersistentDirectoryEntry()
  .then(promise_fileEntry.bind(null, fileName, { create:false }))
  .then(save_fileEntry)
  .then(promise_file)
  .then(promise_fileContent)
  .then(save_fileData)
  .then(remove_fileEntry)
  .then(promise_getPersistentDirectoryEntry)
  .then(promise_fileEntry.bind(null, fileName, {create:true}))
  .then(promise_fileWriter)
  .then(edit_content)
  .then(promise_writeContent)
  .then(promise_getPersistentDirectoryEntry)
  .then(promise_fileEntry.bind(null, fileName, {create:false}))
  .then(promise_file)
  .then(promise_fileContent)
  .then(res => {
      logit('JSON.parse(res.target.result)', JSON.parse(res.target.result));
      // logit('savedFileEntry', savedFileEntry);
      logit('fileData', fileData);
    })
  
  .catch(err => logit('err', err));


function logit(text, obj) {
  console.log(`${text} : `, obj);
}


function promise_getPersistentDirectoryEntry() {
  return new Promise((resolve, reject) => {
    try {
      window.resolveLocalFileSystemURL(cordova.file.dataDirectory, resolve, reject);
    } catch(e) {
      reject(e);
      throw e;
    }
  });
}

function promise_fileEntry(filename, config, dataDirectory) {
  return new Promise((resolve, reject) => {
    try{
      dataDirectory.getFile(fileName, config, resolve, reject);
    } catch(e) {
      reject(e);
      throw e;
    }
  })
}

function promise_file(fileEntry) {
  return new Promise((resolve, reject) => {
    try {
       fileEntry.file(resolve);
    } catch(e) {
      reject(e);
      throw "get_fileFromFileObject error : " + e;
    }
  });
}

function promise_fileContent(file){
  return new Promise((resolve, reject) => {
    try {
      var reader = new FileReader();
      reader.onloadend = resolve;
      reader.onerror = reject;
      reader.readAsText(file);
    } catch(e) {
      reject(e);
      throw e;
    }
  });
}

function save_fileData(fileLoadEvent) {
   console.log('fileLoadEvent', fileLoadEvent)
  try {
    fileData = fileLoadEvent.target.result;
    return fileLoadEvent;
  } catch(e) {
    throw e;
  }
  return result;
}

function save_fileEntry(fileEntry) {
  savedFileEntry = fileEntry;
  return fileEntry;
}

function remove_fileEntry() {
  savedFileEntry.remove();
}

function promise_fileWriter(fileEntry) {
  try{
    return new Promise((resolve, reject) => {
      fileEntry.createWriter(resolve);
    })
  } catch(e) {
    reject(e);
    throw "error in promise_fileEntry : " + e;
  }
}



function promise_writeContent(obj){
  return new Promise((resolve, reject) => {
    try {
      obj.fileWriter.onwriteend = resolve;
      obj.fileWriter.write(obj.data);
    } catch(e){ 
      reject(e)
      throw e;
    }
  });
}

function test(fileEntry) {
  console.log(fileEntry);
}

function editContent(content, fileWriter){
  return fileWriter
}

function edit_content(fileWriter) {
  if(fileData) {
    var savedData = JSON.parse(fileData);
    savedData[new Date().getTime()] = new Date().toString();
    var content = new Blob([ JSON.stringify(savedData, null, 2) ], { type: 'application/json' });
    return {data: content, fileWriter}
  } else {
    var content = new Blob([ JSON.stringify({message: 'first data for this file...'}, null, 2) ], { type: 'application/json' });
    return { data: content, fileWriter }
  }
}